alsa mixers

David Henningsson david.henningsson at
Wed May 8 05:09:15 UTC 2013

On 05/08/2013 12:15 AM, Len Ovens wrote:
> I looked at a number of audio mixers: (I used three audio IFs, an old
> ens1370, An intel HDA (most common internal audio) and an ICE1712
> multitrack card)
>    pavucontrol and kmix: These both control pulseaudio and only affect ALSA
> settings of any sort through the pulse audio interface. kmix is the the
> kde version pavucontrol. There is no reason to attempt to make kmix or
> pavucontrol work without PA running, rather they should stop running
> gracefully if PA is not there.
> I would suggest that pavucontrol be the default PA controller for desktop
> audio that requires it. However, it would make sense to use kmix for the
> kde meta currently planned.
>    ffado-mixer: This is the only choice for FireWire audio right now.
>    HDSPmixer, echomixer and mudita24: These mixers are designed for
> specific audio interfaces and are the best mixer to use in these cases.
>    alsamixer: This comes with alsa and runs in the terminal. It only
> controls alsa. It gives the names alsa uses in its config and is not
> always easy to understand. Alsamixer also is often confused about what is
> an input or an output and the same control may show up in both places or
> be doubled in the same screen. Moving either one of the controls affects
> the other. PA does a great job of selecting the correct
> controls. However, when using jackd(bus), input and output levels need to
> be adjusted at the card.
>    GUI alsa mixers: Interesting thing here. All of them seem to default to
> the pulse master control. This makes me think that pulse calls itself the
> default ALSA card(s). (I can't see alsamixer-gui having pulse code in it)

I think this is because /usr/share/alsa/pulse-alsa.conf has this entry 
in it:

ctl.!default {
     type pulse

...making the default ctl (i e mixer) interface the pulseaudio one.

Alsamixer (the ncurses version) has a specific patch to ignore the 
pulseaudio interface, but you can still get to it if you do "alsamixer 
-D pulse".

> We need a new mixer!Lets think about what a dream recording alsa mixer
> would be like. Then we can think about building it. What controls should
> be available? what screens should be included? What gui tool kit should be
> used? I would think basing the ideas on mudita might be a place to
> start... but then I have not used any of the other HW specific mixers and
> there may be better ideas. I would suggest starting with the Intel HDA and
> AC97 HW.

Before rushing away to write yet another mixer, may I suggest that you 
first look at the current choices a bit and see if it is possible to 
improve them to do what you want? This does not only have the benefit of 
saving you some work to get the basic stuff up and running, it also 
makes the final product fit more use cases than just yours (and as a 
result, you'll get help finding/fixing bugs and so on). And, many 
upstreams are longing for more contributions and a wider user base.

David Henningsson, Canonical Ltd.

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